Lubricating oil containing a polymer of tetradecyl vinyl ether



Patented Mar. 6, 1951 LUBRICATING OIL CONTAINING A POLYMER 1 OFT-ETRADEGYL VINYL ETHER John Mann Butler, Dayton, Ohio, assignor toMonsanto Chemical Company, St. Louis, Mo.,

a corporation of Delaware No Drawing. Application August 21, 1948,

Serial No. 45,580

1 Claim. (01. 252-:s2)

'This invention relatesto the improvement of lubricating oils, and moreparticularly to the reduction of pour points of wax containing mineral Ioils. More specifically'the invention relates to a method of alteringthecrystallization characteristics ofthe' paraffin wax dissolved inlubricating oils, and avoiding the solidification'of the lubricant uponcooling. j a

Many of the commercially available petroleum stocks contain highmolecular weight hydrocarbon waxes, and the lubricating 'oil'iractions,separated by .various refining procedures, contain a substantialproportion dissolved .therein.- Upon cooling these lubricants, .thedissolved waxes crystallize in such form that the mass issolidifled, Itis known that some substances afiec't the crystallization of the'waxa'ndpermit the lu'bri cants to retain their fluidity after coolingto temperatures below the normal pour points of the oils.

The purpose of this invention is to provide a convenient and readilyavailable agent for depressing the pour points of lubricating oils. Afurther purpose of this invention is to enable the selection of aneiiective pour point depressant for a wide variety of wax containinglubricating oils.

The pour points of lubricating oils are measured by a standard A. S. T.M. procedure, by which a sample of oil is heated and then graduallycooled while observing the fluid characteristics of the sample at every5 F. interval, the temperature being multiples of 5 F. The pour point isthe lowest temperature at which the sample is fluid. The details of themethod of determining pour points are set forth in the American Societyfor Testing Materials Bulletin, on petroleum prodnets and lubricantsD-9'7-39.

It has been discovered that there is a critical relationship between thelength of the alkyl group of an alkyl vinyl ether, and the pour point ofa wax containing oil in which the polymer is an efiective pour pointdepressant. Polymers of alkyl vinyl ethers having alkyl groups longer orshorter than the critical length may be less efiective, or entirelyineffective, in depressing the pour point of the same oil. In accordancewith this invention the polymer of tetradecyl vinyl ether is used as apour depressant for wax containing oils having pour points between and50 F. Other polymeric alkyl vinyl ethers are not effective pour pointdepressants for 15 to 50 F. pour oils, and the polymer of tetradecylvinyl ether is not effective in higher or lower pour oils.

In the practice of this invention, the polymerized tetradecyl vinylether is prepared preferably by'the well known low temperature polymerization technique, for example, at temperav tures between l0 F. and+20? F. in the presence of'catalysts, such as aluminum chloride or borontrifluoride. The effectiveness of the polymer as a pour point depressantisnotmaterially affected by the molecular weight of the polymer; thewide range of molecular weights achieved by conventional polymerizationoperation all appear to have the same or very similar. pour pointdepression. The polymerized tetradecyl vinyl ether may be used in anamount varying from 0.01 to 5 percent byweight, but preferred operationinvolves the use of from 0.05 to 2 percent. The polymer is dis persed inthe lubricating oil by adding it directly and stirring the mixture untila homogeneous dispersion, or solution, is effected; It is frequent 1ydesirable to prepare master batches by dispersing large amounts of thepolymerized tetradecyl vinyl ether in a lubricating stock and thereaftermixing the concentrate with a suitable large quantity of the untreatedoil, the proportion being chosen so as to achieve a small but efiectiveproportion of the polymerized tetradecyl vinyl ether in the finallubricant.

This invention may be practiced by using a mixture of polymeric alkylvinyl ethers containing predominantly the polymer of tetradecyl vinylethers, and copolymers of mixed alkyl vinyl ethers containingpredominantly tetradecyl vinyl ethers and substantial portions of nearhomologues, for example, hexadecyl vinyl ether and dodecyl vinyl ether.These copolymers are generally derived from the mixed alcohols asobtained from animal and vegetable oils by saponification and reduction.

The pour point depressant may be used in combination with other knowndepressants and other modifying agents, such as antioxidant anddetergents.

The critical characteristics of pour point depression of lubricatingoils with polymerized vinyl ethers are demonstrated by the followingspecific examples.

Example 1 The critical efiect of the dependent alkyl chain of variouspolymerized alkyl vinyl ethers was demonstrated by preparing one percentby weight solutions of polymerized octyl vinyl ether, polymerized decylvinyl ether, polymerized dodecyl vinyl ether, polymerized tetradecylvinyl ether, polymerized hexadecyl vinyl ether and polymerized octadecylvinyl ether in wax containing lubricating oils having a 20 F. pour pointin the unmodified condition. The six samples of modified oils weretested by means of the standard A. S. T. M. pour point measuring method,and the observed data is set forth in the following table.

Pour Depres- Polymerized agent Pgliint, 55in,

Octyl vinyl ether 20 Decyl vinyl ether 20 0 Dodecyl vinyl ether- 15 5Tetradecyl vinyl ether 0 20 Hexadecyl vinyl ether--- 20 0 Octadecylvinyl ether 20 0 This demonstrates that the polymerized alkyl Example 2For the purpose of demonstrating the criticality of the original pourpoint of the oil upon the degree of pour point depression achieved bymeans of the polymerized tetradecyl vinyl ether, a series of sampleswere prepared by dissolving one percent by weight of polymerizedtetradecyl vinyl ether in samples of oils having pour points varyingfrom 0 to 60 F. The following table sets forth the original and finalpour point as well as the degree of pour point depression achieved.

This data clearly demonstrates that tetradecyl vinyl ether is a goodpour point depressant for 20 F. pour oil and unusually good depressantfor F. pour oil, but that its effect on 60 F. pour oil is almostnegligible. On the other hand, in 0 F'. pour oil, the polymerizedtetradecyl vinyl ether has a deleterious effect in increasing the pourpoint of the oil.

The invention is defined by the following claim:

A lubricating composition which comprises a wax containing minerallubricating oil having an A. S. T. M. pour point of from 15 to F.,containing intimately dissolved therein from 0.05 to 2 percent by weightof a polymer of tetradecyl vinyl ether.

JOHN MANN BUTLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,020,703 Schumann et a1. Nov.12, 1935 2,020,714 Wulfi et a1 Nov. 12, 1935 2,091,627 Bruson Aug. 31,1937 2,389,227 Wright Nov. 20, 1945

